When determining the mass flow of one or more gas components in a gas composed of one or more gas components it is common to assume that some of the gas parameters, such as temperature, gas composition, density, etc, are unchanged in order to enable determination of the mass flow of individual gas components in the composite gas.
However, this may give rise to high measurement uncertainties, since typically such gas parameters may vary over time and hence influence the determination of the mass flow of one or more of the individual gas components. Of course, it is inconvenient since, eg in fermentation processes in breweries, putrefaction processes in putrefaction tanks, gas outlets from biogas plants, etc, it is expedient to be able to determine the individual gas mass flows accurately—either to enable monitoring of the process or to be able to impose users, if any, a tax in response to the mass flow of the one or more of the gas components.
Therefore there is a need for a method of measuring the mass flow of a first gas component in a composite gas, wherein the method is associated with considerably reduced measurement uncertainties compared to the known methods.